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Vitamin B1May 26, 2026~5 min read

Vitamin B1 (Thiamine) Foods — Top Sources Per 100g

Find the best thiamine (vitamin B1) foods ranked by content per 100g. Pork, seeds, and legumes are top sources.


Thiamine: The Energy-Conversion Vitamin

Vitamin B1 (thiamine) is a water-soluble B vitamin that plays a central role in converting carbohydrates into usable energy. It is also essential for nerve function, heart health, and brain metabolism. The FDA Daily Value is 1.2mg per day.

Thiamine deficiency (beriberi) was historically a major problem in populations eating polished white rice. Today, deficiency is most common in people with alcohol use disorder, malabsorption conditions, or restrictive diets.

Top Vitamin B1 Foods (Per 100g, USDA Data)

FoodThiamine (mg/100g)
Pork tenderloin (cooked)0.97
Sunflower seeds1.48
Flaxseeds1.64
Navy beans (cooked)0.23
Lentils (cooked)0.17
Oats (dry)0.76
Fortified breakfast cereal0.5–1.5
Brown rice (cooked)0.19

*Fortified cereal values vary widely — check the nutrition label.

⚡ View full vitamin B1 ranking →

Thiamine and Carbohydrate Metabolism

🔋 Converts carbs → ATP energy

Thiamine is a cofactor for pyruvate dehydrogenase — the enzyme that converts glucose into acetyl-CoA for the Krebs cycle. Without enough B1, energy production from carbohydrates becomes inefficient.

🧠 Critical for brain function

The brain relies almost entirely on glucose for energy. Severe thiamine deficiency causes Wernicke encephalopathy — a serious neurological condition involving confusion and vision problems.

🍺 Alcohol depletes thiamine

Alcohol impairs thiamine absorption in the gut and increases excretion. Heavy drinkers have dramatically higher thiamine requirements and should consider supplementation.

Key Takeaways

  • Pork is the richest meat source of thiamine — one serving covers 80%+ of daily needs
  • Seeds (sunflower, flaxseeds) are excellent plant-based sources of B1
  • Whole grains contain significantly more thiamine than refined grains
  • Thiamine is destroyed by cooking heat — avoid overcooking B1-rich foods
  • High carbohydrate intake increases thiamine requirements — balance your diet

Data Source

USDA FoodData Central — Foundation Foods & SR Legacy (Public Domain)


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